Defibrillation waveform and post-shock rhythm in out-of-hospital ventricular fibrillation cardiac arrest.

BACKGROUND The importance of the defibrillation waveform on the evolving post-shock cardiac rhythm is uncertain. The primary objective of this study was to evaluate cardiac rhythms following the first defibrillation shock, comparing biphasic truncated exponential (BTE), monophasic damped sinusoidal (MDS), and monophasic truncated exponential (MTE) waveforms in patients experiencing out-of-hospital ventricular fibrillation cardiac arrest (OHCA). METHODS We reviewed the automated external defibrillator (AED) and emergency medical services (EMS) records of 366 patients who suffered OHCA and were treated with defibrillation shocks by first-tier emergency responders between 1 January 1999 and 31 August 2002 in King County, Washington. The post first shock rhythms were determined at 5, 10, 20, 30, and 60 s and compared according to defibrillation waveform. RESULTS The MDS and BTE waveforms were associated with significantly higher frequency of defibrillation than the MTE waveform, though only the BTE association persisted to 30 and 60 s. No difference in defibrillation rates was detected between MDS and BTE waveforms. By 60 s, an organized rhythm was present in a greater proportion for BTE (40.0%) compared with MDS (25.4%, P=0.01) or MTE (26.5%, P=0.07). CONCLUSION In this retrospective cohort investigation, MDS and BTE waveforms had higher first shock defibrillation rates than the MTE waveform, while patients treated with the BTE waveform were more likely to develop an organized rhythm within 60 s of the initial shock. The results of this investigation, however, do not provide evidence that these surrogate advantages are important for improving survival. Additional investigation is needed to improve the understanding of the role of waveform and its potential interaction with other clinical factors in order to optimize survival in OHCA.

[1]  D J Roe,et al.  Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model. , 1997, Circulation.

[2]  H. Calkins,et al.  Comparison of a novel rectilinear biphasic waveform with a damped sine wave monophasic waveform for transthoracic ventricular defibrillation. ZOLL Investigators. , 1999, Journal of the American College of Cardiology.

[3]  R. Kerber,et al.  Truncated exponential versus damped sinusoidal waveform shocks for transthoracic defibrillation. , 1996, The American journal of cardiology.

[4]  J J Heger,et al.  Sudden cardiac death. , 1998, Circulation.

[5]  George A. Johnson,et al.  Truncated biphasic pulses for transthoracic defibrillation. , 1995, Circulation.

[6]  M. Copass,et al.  Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation , 1999, JAMA.

[7]  J. Ornato,et al.  Improving survival from sudden cardiac arrest , 1991 .

[8]  Wanchun Tang,et al.  Adverse Outcomes of Interrupted Precordial Compression During Automated Defibrillation , 2002, Circulation.

[9]  R. Kronmal,et al.  Multicenter comparison of truncated biphasic shocks and standard damped sine wave monophasic shocks for transthoracic ventricular defibrillation. Transthoracic Investigators. , 1996, Circulation.

[10]  P. Steen,et al.  Effects of Interrupting Precordial Compressions on the Calculated Probability of Defibrillation Success During Out-of-Hospital Cardiac Arrest , 2002 .

[11]  Dispatcher-assisted cardiopulmonary resuscitation and survival in cardiac arrest. , 2002 .

[12]  Wanchun Tang,et al.  Adverse effects of interrupting precordial compression during cardiopulmonary resuscitation. , 1997, Critical care medicine.

[13]  J. Ornato,et al.  Improving survival from sudden cardiac arrest: the "chain of survival" concept. A statement for health professionals from the Advanced Cardiac Life Support Subcommittee and the Emergency Cardiac Care Committee, American Heart Association. , 1991, Circulation.

[14]  Y. Sato,et al.  High-energy defibrillation increases the severity of postresuscitation myocardial dysfunction. , 1997, Circulation.

[15]  J. Ruskin,et al.  Relation between shock-related myocardial injury and defibrillation efficacy of monophasic and biphasic shocks in a canine model. , 1994, Circulation.

[16]  K. Monsieurs,et al.  Equivalence of the standard monophasic waveform shocks delivered by automated external defibrillators? , 2002, Resuscitation.

[17]  R. White,et al.  Electrocardiographic evaluation of defibrillation shocks delivered to out-of-hospital sudden cardiac arrest patients. , 1999, Resuscitation.

[18]  James K. Russell,et al.  Multicenter, Randomized, Controlled Trial of 150-J Biphasic Shocks Compared With 200- to 360-J Monophasic Shocks in the Resuscitation of Out-of-Hospital Cardiac Arrest Victims , 2000, Circulation.

[19]  P. Tchou,et al.  Multicenter study of principles-based waveforms for external defibrillation. , 2001, Annals of emergency medicine.

[20]  Richard C. Nova,et al.  A comparison of biphasic and monophasic shocks for external defibrillation. Physio-Control Biphasic Investigators. , 2000, Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors.

[21]  I. Stiell,et al.  Out-of-hospital defibrillation with automated external defibrillators: postshock analysis should be delayed. , 2001, Annals of emergency medicine.

[22]  J. Engdahl,et al.  The epidemiology of out-of-hospital 'sudden' cardiac arrest. , 2002, Resuscitation.